Unical NUA, Installation And Maintenance Instructions Manual

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4.5.2 - DIMENSIONING
The negative pressure (draught) of a chimney also depends on
its height. Check the negative pressure in the chimney, which
must correspond with the values given in the technical charac-
teristics of the product.
The minimum chimney height is 3.5 metres.
The inner section of the chimney can be round (this is the best),
square or rectangular (the ratio of the inner sides must be ≤1.5)
with the sides joined with a minimum radius of 20 mm. The
cross-section size must be a minimum of Ø100mm.
Chimney cross-sections/lengths must be correctly dimensioned
according to the general calculation method of UNI EN13384-1
or other proven methods.
4.5.3 - MAINTENANCE
The chimney must always be clean, as deposits of soot or
unburned oils reduce its cross-section, blocking its draught,
impairing the proper functioning of the stove and, if in large
quantities, can catch fire. It is mandatory to have the chimney and
the chimneypot cleaned and inspected by a qualified chimney
sweep at least once a year, and at the end of the inspection/main-
tenance to have a signed report issued that the system is safe.
Failure to clean jeopardises the safety of the system.
4.5.4 - FLUE GAS DUCT
The connection between the stove and the chimney must be
made with a smoke duct in accordance with EN 1856-2.
The connection section must be a maximum of 4 m long in
horizontal projection, with a minimum slope of 3% towards the
smoke outlet and with a maximum number of 3 bends at 90°
(available for inspection - the smoke outlet T-union of the stove
must not be counted).
The diameter of the smoke duct must be equal to or greater
than that of the appliance outlet (Ø 80 mm).
Use ducts with a diameter of 80 mm or 100 mm depending
on the type of system, with silicone gaskets or similar sealing
devices that can withstand the operating temperatures of the
appliance (min. T200 class P1).
The use of flexible metal, fibre cement or alumini -
um pipes is prohibited. For changes of direction,
it is recommended to always use a Tee fitting with
an inspection cap, which allows easy periodic cleaning of the
pipes. Always ensure that after cleaning, the inspection caps
are tightly closed again with their gasket intact.
It is forbidden to connect more than one appliance or the ex-
haust from overhead hoods into the same smoke duct.
The direct wall exhaust of combustion products to enclosed or
open spaces is prohibited.
The smoke duct must be at least 400 mm away from flammable
or heat-sensitive construction elements.
KEY
U INSULATION
V EVENTUAL REDUCTION FROM 100 TO 80 mm
I INSPECTION CAP
S INSPECTION DOOR
P AIR INTAKE
T
TEE FITTING WITH INSPECTION CAP
A
MINIMUM 40 mm
B
MAXIMUM 4 m
C
MINIMUM 3°
D
MINIMUM 400 mm
E
HOLE DIAMETER
F
SEE FIGURES par. 4.4
4.5.5 - CHIMNEY
Chimneys must meet the following requirements:
- have a useful outlet cross-section not less than twice that of
the chimney/piped system on which it is inserted;
- be shaped in such a way as to prevent rain and snow from
entering the chimney/piped system;
- be so constructed that, even in the case of winds from all
directions and at any inclination, the evacuation of combus-
tion products is ensured.
4.5.6 - EXAMPLES OF CORRECT INSTALLATION
1. Installation of Ø120mm chimney with perforation for pipe pas-
sage increased by:
minimum 100mm around the pipe if communicating with
non-flammable parts such as concrete, bricks, etc.; or
minimum 300mm around the pipe (or as prescribed in the
data plate) if communicating with flammable parts such as
wood etc.
In both cases, insert suitable insulation between the chimney
and the ceiling.
It is recommended to check and comply with the nameplate
data of the chimney, in particular the safety distances to com-
bustible materials.
The above rules also apply to holes drilled in walls.
2. Old chimney, ducted minimum Ø100mm with the construction
of an external door to allow cleaning of the chimney.
3. External chimney made exclusively from insulated stainless
steel pipes, i.e. double-walled minimum Ø100 mm: all well
anchored to the wall. With windproof chimneypot.
4. Ducting system via Tee fittings allowing easy cleaning without
dismantling the pipes.